On what OS are you trying to clone the sd card? Windows, Linux?
I’d do it on Linux (Raspian, debian) with the dd command. This guide turned up on my first google search, three years old, but still valid. https://beebom.com/how-clone-raspberry-pi-sd-card-windows-linux-macos/
But if you have a clean install, than simply do the same flashing twice with Etcher on different sd cards, the system is exactly the same, even the unique ids are the same. After that you can easily work with the snapshots.